Emona ETT-202 DATEx for NI ELVIS: Trainer Demonstration
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Introduction
The Emona DATEx is an add-on board for the NI ELVIS™ platform.
The NI ELVIS™ / Emona DATEx combination allows a broad range of introductory telecommunications experiments to be implemented.
The ELVIS™/DATEx combination provides a hands-on learning environment for students to see the fundamental math and theory of telecommunications implemented with real-world electrical signals.
The ELVIS™/DATEx combination fully utilizes the capabilities of the NI ELVIS™ Virtual Instrumentation and LabVIEW™ programming language.
The DATEx board can be controlled both MANUALLY (finger adjustment of all knobs and switches), as well as remotely, under PC-CONTROL where all knobs and switches are varied under NI LabVIEW™ control using the DATEx Main Soft Front Panel (SFP) and DATEx ToolBar SFP.
Low-level LabVIEW™ VI's are also provided to allow DATEx hardware circuit blocks to be integrated into LabVIEW program flow - to implement "hardware-in-the-loop" applications.
Emona DATEx Front Panel
Functions used in sections "A", "B" and "C"
NOTE: ensure the MANUAL / PC-CONTROL switch is in the MANUAL position for section "A", "B" and "C" of this demonstration.
How DATEx Models Equations
(A1) Modeling Equations – multiplication of 2 sine waves
Points to note:
Telecoms is Math and TIMS models Math
The 2kHz and 100kHz MASTER SIGNALS module outputs are synchronized providing textbook-like displays
Refer to Lab Manual Experiments:
DSBSC - Generation
Product Demodulation
(A2) Modeling Equations - Addition of 2 Signals
Points to note:
Knobs do not have calibration marks – students need to measure all parameters
Front panel conventions – easy to use
Building the equation block-by-block – hands-on learning
Inputs are high impedance & outputs are low impedance – amplitudes remain stable
(A3) Modeling Equations – combining addition & multiplication
Points to note:
Building the equation creates the modulation system
Textbook images on the scope see carrier & message frequencies simultaneously
Refer to Lab Manual Experiments:
AM modulation
Envelope detection
Modeling equations
(A4) Modeling Equations – Conclusions
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DATEx brings the Math and block diagrams to life
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DATEx offers a selection of signal sources
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2kHz SINE at MASTER SIGNALS module for base band
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NI ELVIS™ FUNCTION GENERATOR module for carrier & base band signals
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SPEECH for students to observe the human voice
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DATEx uses real-time electrical signals in a “hands-on” learningenvironment
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DATEx provides active, “hands-on” modeling
Digital Modulation
(B1) Digital Modulation – introduction to digital sequences
Points to note:
SEQ. GEN. is a source of repetitive data at any clock rate
Other data sources are: PCM Encoder module and External signal generators
The digital data Sequence is fixed
Front panel conventions – square = digital signals, circle = analog level signals
inputs on the left, outputs on the right
(B2) Digital Modulation - BPSK
In the same way that we multiplied 2 analog signals to make DSBSC, now we will multiply a data stream with a carrier to make BPSK
Points to note:
Textbook-like images on the scope – see carrier phase inversions
The 8kHz and 100kHz MASTER SIGNALS module signals are synchronized
Change SEQ. GEN. clock to 100kHz TTL for a better illustration of phase inversions
Refer to Lab Manual Experiments:
BPSK modulation; BPSK demodulation
The noisy channel model; DPSK and BER
QPSK modulation and demodulation
(B3) Digital Modulation - ASK
ASK can be generated with a switch or by multiplication. DATEx can do both.
Here we demonstrate multiplication using the same set-up as for BPSK
Points to note:
Textbook-like images on the scope
Can also add band limiting (filtering) and do recovery
Refer to Lab Manual Experiments:
ASK Generation; ASK Demodulation
(B4) Digital Modulation - Conclusions
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Pseudo-random sequences are used
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BPSK and ASK modulation schemes were introduced
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NOISY CHANNEL can be implemented
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Can also build QPSK easily
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Eye diagrams can be viewed easily
Sampling, PAM, and TDM
(C1) Sampling, PAM & TDM - Introducing the TGP module
Points to note:
The Twin Pulse Generation module creates control signals for sampling switches and delays for multiplexing samples
IMPORTANT:
As "Delay" is varied in the following examples, note that the outputs Q1 and Q2 are no longer valid when Q2 overlaps Q1.
ALWAYS start with DELAY and WIDTH set to minimum (counter clockwise).
(C2) Sampling, PAM & TDM - Sampling, PAM
Introduction to Pulse Amplitude Modulation
Refer to Lab Manual Experiments:
Sampling and Reconstruction
ALWAYS start with DELAY and WIDTH set to muinimum (counter clockwise).
(C3) Sampling, PAM and TDM - Sampling and Recovery
Points to note:
Sampling can be investigated
Nyquist limit can be tested
Speech can be introduced and sampling rate effects listened to
Refer to Lab Manual Experiments:
Sampling and Reconstruction
(C4) Sampling, PAM & TDM - Time Division Multiplexing
Now we can use both switches, and both control pulses from the TPG module, to create a 2-channel TDM signal
Refer to Lab Manual Experiments
PAM and TDM
PCM Encoding
PCM-TDM
(C5) Sampling, PAM & TDM - Conclusions
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Important concepts can be viewed easily
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Students learn through settings up experiments and taking measuremnts; as well as, through simple observation
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All parameters can be varied, e.g. pulse width, spacing, filtering
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Good background for introducing PCM modules
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Speech or any other signal can be introduced and studied
PC-Control
(D) PC-CONTROL of the Emona DATEx Trainer
Below are printouts of the two Emona DATEx Soft Front Panels.
DATEx SFPs only run under NI LabVIEW™.
Emona DATEx Main SFP
Emona DATEx Toolbar SFP
How to control Emona DATEx under DATEx SFP's
The circuit blocks ADDER, AMPLIFIER, PCM ENCODER, PHASE SHIFTER, SEQUENCE GENERATOR, TUNEABLE LPF & TWIN PULSE GENERATOR all have adjustable controls, either potentiometers or switches.
To enable PC-CONTROL:
Slide the MANUAL / PC-CONTROL front panel switch to the PC-CONTROL position.
Launch either the Emona_DATEx_Main SFP or Emona_DATEx_ToolBar SFP
(See APPENDIX "A" for installation instructions).
LabVIEW™ SFP Control of DATEx Knobs and Switches:
Left click on the control and use the mouse to rotate the knob or toggle the switch as required.
Note that TAB, left arrow and right arrow keys can also be used.
Repeat any of the experiment examples "A", "B" or "C" to demonstrate the PC-CONTROL functionality.
APPENDIX A Equipment Required, Set-up and Installation
Equipment Required for demonstration:
1. NI ELVIS™ platform with power supply
2. NI™ USB-6251 DAQ interface (or faster) with power supply
3. Emona ETT-202 DATEx telecommunications trainer kit, including:
1 x DATEx board
20 x patch cords
3 x 2mm-BNC scope cords
2 x 2mm-4mm DMM cords
Emona DATEx CD-ROM
1 x headphones
1 x ETT-202 User Manual and Lab Manual
4. NI LabVIEW™ installed on a PC
Set-up of the NI ELVIS™ AND DATEx hardware:
Connect and power-up NI ELVIS™, USB-6251, PC and launch LabVIEW™.
Carefully follow the installation instructions as per the supplied NI™ manuals.
Installation and running the Emona DATEx SFPs:
LabVIEW™ must be installed on your PC to run the Emona DATEx SFP's.
To install the Emona DATEx SFPs:
Insert the Emona DATEx CD-ROM in your CD-drive and click "Emona_DATEx_setup.exe".
After installation has been completed, go to
Windows START > Programs > Emona_DATEx
Select either Emona_DATEx_Main or Emona_DATEx_ToolBar from the menu to launch the required SFP.
Additional Resources
Developer Zone: Emona ETT-202 DATEx for NI ELVIS Product Page
Developer Zone: Emona ETT-202 DATEx for NI ELVIS Resource Page
Developer Zone: Emona ETT-202 DATEx for NI ELVIS FAQ: Part 1
Developer Zone: Emona ETT-202 DATEx for NI ELVIS FAQ: Part 2
Developer Zone: Emona ETT-202 DATEx for NI ELVIS FAQ: Part 3
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